What type of card is Unknown Event?

Q: What type of card is Unknown Event?

Unknown Event is a Phenomenon. Its oracle text reads: "When you encounter this, Each player opens a Magic the Gathering booster pack. They may select up to two cards from that pack and exile them face down. For the rest of the game, players may look at and play cards exiled this way without paying their mana costs. (Then Planeswalk away from this phenomenon.)"

Unknown Event

Phenomenon

When you encounter this, Each player opens a Magic the Gathering booster pack. They may select up to two cards from that pack and exile them face down. For the rest of the game, players may look at and play cards exiled this way without paying their mana costs. (Then Planeswalk away from this phenomenon.)

Set Black Lotus Unknown Planechase

Rarity Common

Collector # PLA010

Scryfall